Browse, graze, mate: Food and company help animals in captivity

From tongue rolling alpacas to irritable yaks and perturbed pigs, new research has lifted the lid on why some farm and zoo animals cope well with captivity and others display signs of stress.

Researchers from Aberystwyth and Portsmouth universities in the UK have published the first large-scale study to identify which species of hoofed animals, known as ungulates, are better suited to captive environments and which require better husbandry if kept in captivity.